Iraq today pledged to shut down the operations of Kurdish fighters operating in the country amid frantic efforts to head off a Turkish attack.

The Iraqi prime minister, Nuri al-Maliki, called the Kurdistan Workers party (PKK) a "terrorist organisation" and announced that he would "shut down their offices".

The move came as the US and Iraq attempt to avert a threatened invasion by Turkish troops looking to crush PKK fighters operating on the Iraqi border.

"The PKK is a terrorist organisation and we have taken a decision to shut down their offices and not allow them to operate on Iraqi soil," Mr Maliki said.

"We will also work on limiting their terrorist activities, which are threatening Iraq and Turkey."

He gave no details of how the fighters could be prevented from launching attacks from their remote mountain bases in northern Iraq.

Earlier today, the Turkish prime minister, Recep Tayyip Erdogan warned that his country could not "wait forever" as troops lined the Iraqi border in preparation for an attack on Kurdish guerrillas.

The guerrillas have been responsible for the deaths of around 40 Turkish soldiers over the past month.

Mr Erdogan - who was last week given a mandate by the Turkish parliament to order a military incursion into northern Iraq - was speaking after talks with Gordon Brown in Downing Street.

He has come under increasing pressure from the Turkish public and military to sanction a cross-border assault following a weekend attack by PKK fighters in south-east Turkey in which at least 12 soldiers died. A further eight remain missing.

"We condemn absolutely and unequivocally the terrorist violence of the PKK," he added. "The fact that 12 members of the Turkish army have been killed, the fact that eight have been kidnapped ... is something that the whole world community has condemned over the past few days."

Mr Erdogan reassured Iraq that Turkey would "continue to support the Iraqi people", but appeared to criticise Baghdad for not doing more to combat the PKK.

He said that it was forbidden "within the framework of international law" for a state to allow a terrorist organisation to operate from inside its borders, adding that he had met the Iraqi government four times to discuss the threat posed by the PKK.

"Despite all of these efforts, we have some expectation with what is to be done about the terrorist organisation in the north of Iraq," he added. "The Iraqi government must know that we can exercise the mandate [at] any time. We cannot wait forever."

Earlier, the Turkish foreign minister, Ali Babacan, rejected any ceasefire by Kurdish fighters as he met Iraqi leaders in Baghdad and urged them to crack down on the PKK.

"Ceasefires are possible between states and regular forces," he said. "The problem here is that we are dealing with a terrorist organisation."

However, Mr Babacan expressed his willingness to employ "political dialogue, diplomacy, economic and cultural tools as well as military measures".

The Iraqi foreign minister, Hoshiyar Zebari - himself a Kurd - called the crisis "complex and grave". Mr Zebari said he hoped a diplomatic push would help stave off any incursion.

Iraqi and US leaders have warned that a Turkish intervention would threaten peace in northern Iraq - the one stable area in the war-torn country.

The Iraqi president, Jalal Talabani, also a Kurd, yesterday held out the prospect of the PKK announcing a unilateral ceasefire.

The PKK called on Turkey not to attack Iraq, claiming a unilateral ceasefire, declared in June, was still in place although fighting had not stopped.

"We have not officially ended the ceasefire," the group said, the pro-Kurdish Firat news agency reported. "We're stating clearly that, if the Turkish state stops its attacks, increased tensions will be replaced with a clash-free environment."

Turkey has deployed up to 100,000 troops, backed by tanks, F16 fighters and helicopter gunships along its Iraqi border. It estimates that 3,000 PKK rebels are based in Iraq.

The US president, George Bush, yesterday expressed his "deep concern" about the Kurdish fighter attacks. Mr Bush held talks with the Iraqi prime minister, Nuri al-Maliki, and the two agreed to work with Turkey to stop the PKK strikes.

The US secretary of state, Condoleezza Rice, and the British foreign secretary, David Miliband, said they had proposed a meeting of US, Turkish and Iraqi officials to discuss how to stop the attacks.

The PKK claims to have captured the eight Turkish soldiers missing since Sunday.

A spokesman said they were seized during fighting and would be treated with respect, but insisted it was "premature" to talk about their release.

"We are responsible for the safety of the captives in compliance with international laws," Abdul-Rahman al-Chadarchi told the Associated Press.

"The soldiers were seized as they were attacking our forces. They are all in good shape. When the Turkish government asks for them, we can talk about conditions."